Establishment of an in vitro apoptosis model of rat nucleus pulposus cells

  Objective: To establish an in vitro apoptosis model of rat intervertebral disc nucleus pulposus cells. Methods: In order to fully simulate the microenvironment of degenerative intervertebral disc nutrient deficiency, this experiment used DMEM medium containing 1%, 3%, 5%, 8%, and 10% fetal calf serum to culture intervertebral disc nucleus pulposus cells, and the best selection was Pro-apoptotic concentration, respectively detect nucleus pulposus cell apoptosis rate, apoptosis-related protein Bax, bcl-2, caspase-3 enzyme expression, cell proliferation curve and immunofluorescence analysis. Results: The apoptosis rate of nucleus pulposus cells measured by flow cytometry increased with the decrease of fetal bovine serum (FBS) concentration. 3% FBS was the most effective concentration inducing apoptosis; Western blot showed that Bax and caspase-3 enzymes were expressed in The 3% FBS group was significantly higher than the 10% FBS group, and the expression of bcl-2 decreased; CCK-8 test results showed that in the medium containing 3% FBS, as the apoptosis rate increased, the proliferation rate of nucleus pulposus cells increased. The slower the immunofluorescence analysis of FAS expression in 3% FBS group was significantly higher than that in 10% FBS group.

   Conclusion: 3% FBS can induce apoptosis of nucleus pulposus cells, which will eventually lead to the loss of cell function. The caspase family participates in and executes this process.